Jet operated device for circulating or compressing a fluid



Sept. 26, 1961 B. J. M. SALMON ETAL 3,001,691

JET OPERATED DEVICE FOR CIRCULATING OR COMPRESSING A FLUID Filed Jan. 6,1959 3 Sheets-Sheet 1 INVENTORS BENJAMIN JEAN MARCEL SALMON 8| JEANHENRI BERT! Sept. 26, 1961 B. J. M. SALMON ETAL 3,001,691

D DEVICE FOR CIRCULATING OR COMPRESSING A FLUID JET OPERATE Filed Jan.6, 1959 3 Sheets-Sheet 2 INVENTORS BENJAMIN JEAN MARGEL 'SALMON 8| JEANHENRI BETIN Sept 1951 B. J. M. SALMON ErAL 3,001,691

JET OPERATED DEVICE FOR CIRCULATING OR COMPRESSING A FLUID Filed Jan. 6,1959 3 Sheets-Sheet 3 INVENTORS BENJAMIN JEAN MARCEL SALMON 8 JEAN HENRITIN BY I United States Patent 3,001,691 JET OPERATED DEVICE FORCIRCULATING 0R CONIPRESSENG A FLUID Benjamin Jean Marcel Salmon,Suresnes, and Jean Henri Bertln, Neuilly-sur-Seine, France, assignors toSociete Bertin & Cie, Paris, France, a company of France Filed Jan. 6,1959, Ser. No. 785,279 Claims priority, application France Jan. 9, 19582 Claims. (Cl. 230-108) The transfer of energy from a primary orenergizing flow to a secondary or induced flow to drive the latter flow,can be carried out in two different well known ways: (a) by tangentialaction and mixture, in continuous operation, or (b) by thrust orsandwiching, in intermittent flow.

The conventional jet ejector illustrated in FIG. 1 of the accompanyingdrawings in an example of (a) and comprises a mixing chamber 2 followingthe nozzle 1 discharging the primary or energizing jet; the inducedfluid is entrained, as shown by the arrows f into this chamber which isextended by a diffuser 3 opening into the zone to be fed.

This operation takes place with very poor efi'iciency owing to thelosses due to the formation of the mixture and to the unavoidablevortices.

In the case of ([2), primary flow is no longer in the form of acontinuous jet but in the form of a succession of pufls which push infront of them, as would a piston, slices of secondary fluid enclosedbetween the puffs.

FIG. 2 of the accompanying drawings illustrates a device of this kind.

A puflf of primary fluid is shown at 4 as it issues from the nozzle 1.It drives in front of it, through the convergent-divergent duct 5, aslice of secondary fluid 6 behind the previous puff 4a which itselfpushes before it the previous slice of secondary fluid 6a, which liesbehind an earlier puff 4b, and so on. Discharge takes place in thesystem to be fed, which is the atmosphere in the illus trated example,the device being then used to augment the thrust of the hot gaseous flowgenerated in a pulsatory combustion chamber.

This pulsatory drive, acting normally or perpendicularly to the sectionsof induced fluid, yields high efliciences, but may lead to technicaldiificulties.

The present invention has for its object to combine the normal actionwith the tangential action and to allow, starting with a permanentenergizing jet and requiring but a relatively simple mechanical device,transfer to the induced flow of an important fraction of the availableenergy, by normal or frontal action.

In the accompanying drawings:

FIGS. 1 and 2 are explanatory diagrams which have been referred toabove.

FIG. 3 is an axial section of an embodiment of the invention.

FIG. 4 is a section on an enlarged scale taken along the line IV-IV ofFIG. 3, illustrating the generation of spirals formed by the energizingfluid.

FIG. 5 is an axial section of another embodiment with a helical jet.

FlGS. 6 to 9 are similar sections of four additional embodiments.

FIG. is a section of a detail of FIG. 9, on an enlarged scale, takenalong line XX of this figure.

In the embodiment of FIGS. 34, a stationary casing is formed by twoflanges 7 and 8 which converge slightly towards the periphery, i.e.whose spacing gradually decreases from the axis AA of the machine to theperiphery, so as to keep a roughly constant radial passage area, as in acompressor. .The flanges comprise, along the axis, one or two inlets 9,10 for sucking induced fluid and, at

3,001,692 Patented Sept. 26, 1961 their periphery, the flanges areconnected to a volute 11 adapted to collect the compressed fluid. Ahollow shaft 12 rotates about axi AA. This shaft is driven by a motor(not shown) and its bore 13 is fed with energizing fluid under pressure.This fluid issues from slot-like nozzles 14, 14a, which are directedparallel to the axis AA and which are located at the end of radial arms15, 15a which are fast with the shaft 12. The energizing fluid isdischarged by the slots 14, 14a in the form of two flat opposite jetswhich, during the continuous rotation of shaft 12, sweep the spacecomprised between the flanges 7 and 8 and extending around axis AA.

FIG. 4 illustrates this operation. Only one of the arms 15, rotating inthe direction of arrow 1, and the corressponding slot 14 extendingperpendicularly to the plane of the figure, have been drawn. One of theflanges 8, and the circle 8a corresponding to the connection of thisflange with the volute 11, are seen. Owing to the composition of thetangential velocity u at which the slot 14 moves, with the velocity w ofthe ejected primary fluid relatively to the slot, the fluid issues withan oblique absolute velocity v and moves at this velocity through thespace comprised between flanges 7 and 8. (The velocities are not drawnto scale on the figure because they are much too high and may reachseveral hundreds of meters per second.)

If the origin of time, or zero time, is taken as corresponding to theposition of the members shown in FIG. 4, at the time z slot 14 was at aThe fluid then ejected has reached at zero time, the distance a f beingequal to the product of v by the time difference t At the time -2t slot14 was at a and the fluid it has ejected has reached f at zero time, thedistance a f being equal to the product of v by 2t and so on. Therefore,at zero time, the fluid previously ejected by the slot 14 lies on aspiral S This spiral moves through the space between flanges 7 and 8. Atthe time +1 slot 14 reaches (1' and the fluid spiral at 5' pushes infront of it, towards volute 11, the primary fluid which has enteredthrough inlets 9 and 10.

The opposite slot 14a (not shown in FIG. 4) operates similarly: at zerotime, the fluid ejected by this slot lies on a spiral S which moves inlike manner.

The device thus constitutes a sort of centrifugal compressor with fluidvanes. As the spirals move, they exert a frontal action on the inducedfluid and this frontal action is a cause of good efliciency.

The above explanation is, of course, theoretical since the inducing jetissuing from the slots is assumed to maintain it velocity. However, asthe inducing fluid moves away from the slots, the jet formed at theoutlet of the slots loses its stiffness, and it spreads out anddeteriorates through tangential action and vertical mixture with theinduced fluid. This action entails unavoidable losses, but theefliciency is higher than that which is obtainable with a purelytangential action as in the case of FIG. 1. On the other hand, it isconvenient to be able to use a continuous inducing jet, contrary to thedevice of FIG. 2 which requires a pulsating jet.

ln the embodiment of FIG. 5, the nozzle 16 forming the inducing jet,rotatesabout axis AA which is parallel to the axis of said nozzle but isshifted radially, and is disposed at the inlet of a convergent-divergentduct 18 of revolution about axis AA and comprising a central body 19, sothat the axis of the nozzle describes the medial line of an annularorifice 20 bounded by body 19 and the Wall 18.

Referring to the analysis shown in FIG. 4 (although in this case theflow is rather more complex since it does not lie in a plane), it willbe observed that the flow of inducing fluid has a helical shape andpropagates through the space comprised between the duct 18 and thecentral body, driving before it, by frontal and tangential action, theinduced fluid entering the orifice 20. Duct 18 and central body 19 mustbe so shaped that the helical inducing jet sweeps'the space betweenthese members while remaining tangential to them. Theoretically, themean stream-line of the jet ought to describe (neglecting velocityretardation) a single-sheet revolution hyperboloid about axis AA. Inpractice, the spreading out of the jet and its retardation will be takenexperimentally into account, in order to determine more accurately theadequate wall outlines.

It is advantageous to replace the cylindrical jet by a jet ofrectangular shape or, better still, by a sheet-like jet issuing from athin slot-like nozzle, as in FIGS. 3 and 4. The delimitation of theboundary between the inducing and induced flows is then effected in amore regular way, the separating surfaces having, at the start,rectilinear directrices (FIG. 6).

As in the case of FIG. 3, it is possible to use two or more nozzles 16,16a (FIG. 7) rotating synchronously, to generate two or more inducingjets.

In the arrangement of FIG. 8, the nozzles 16, 16a generating theinducing jets are inclined with respect to the axis AA of the system, ina direction opposite to the direction of rotation so as to reduce themagnitude of the tangential component. This arrangement may beparticularly useful in the case where the ejection velocity of theinducing jet is too small in comparison with the tangential linearvelocity of the nozzles.

The same arrangement is easily applicable to the case of FIGS. 3 and 4,by imparting to the relative velocity w a tangential component, ie byusing a nozzle whose blowing slot 14 is inclined with respect to theradius.

In the embodiment of FIGS. 9 and 10, the inducing jets in the form offlat sheets are generated by radial slots 22, 22a extending on hollowradial arms 23, 23a which are fast with the hollow rotary shaft 12. Asshown in FIG. 10, the slots 22, 22a may be inclined in order to impartto the injection velocity of the inducing sheet a tangential componentwhich, according to the direction of inclination, is subtracted from therotation velocity of the nozzle, or is added thereto.

This inclination of the nozzles, such as that of the nozzles shown inFIG. 8, may be used to insure, by reaction, rotation of the shaft 12carrying them, thus avoiding the use of a motor for driving this shaft.

The radial arms may, of course, be more numerous, for instance there maybe 3 or 4 of them. They will preferably be so shaped as to reduceresistance to the induced fluid and possibly to have a favorableinteraction with this fluid. Thus, reaction of the fluid on the arms maycontribute to their rotation, provided they are shaped as motive vanessimilar to turbine vanes, or else, the driving of the arms by a motor orby reaction of the inducing flows may contribute directly to driving theinduced flow, provided the arms are shaped as compressor vanes or screwblades. This latter case is illustrated in FIG. 10.

A similar arrangement may be applied to the device of FIGS. 3 and 4, byfixing on shaft 12, close to the inlets 9 and 10, vanes or screw bladeshaving a motive or compressive action as set forth above;

All the above-described devices may be operated both with liquid andgaseous flows; Mixed solutions can also be considered, with one of theflows being liquid and the other gaseous.

The applications of the invention are numerous.

The embodiment of FIGS. 3 and 4 is specifically directed to the case ofa compressor or fan, whereas the other embodiments may be operatedeither as compressors or fans, or as jet propulsion units, or asaircraft sustainers or lift producers, the mixture of inducing fluid andinduced air in that case issuing into the atmosphere. According to theparticular application, the axis AA will be horizontal or vertical.

What we claim is:

1. An ejector device comprising, in combination, alongitudinally-extending duct having a peripheral wall with said walldefining a convergent inlet end for said duct and said duct beinggenerally divergent away from said convergent inlet end, a hollow rotaryshaft coaxial with said duct and disposed at said inlet end, a pluralityof hollow vane-shaped arms integral with and extending radially fromsaid hollow shaft toward said wall at said inlet end but the ends ofsaid arms terminating short of said wall and the trailing edges of saidvane-shaped arms extending substantially in the transverse plane ofsmallest cross-section of said duct wherein the convergent portion ofsaid wall is connected to the divergent portion thereof, the interior ofsaid hollow arms communicating with the interior of said hollow shaft,slot-like nozzles formed on said arms and extending along the trailingedges thereof, said nozzles communicating with the interior of saidhollow arms, said shaft being adapted to be connected to a supply offluid under pressure for supplying pressure fluid to said nozzlesthrough the interior of said shaft and said arms, whereby the fluid inissuing from said nozzles forms thin laminar jets directed to move alongsaid duct in a generally helical path.

2. An ejector device as defined in claim 1, wherein each slot-likenozzle is oriented in a direction which is inclined with respect to theradial plane of its arm.

References Cited in the file of this patent UNITED STATES PATENTS1,067,883 Skifflngton July 22, 1913 1,653,189 Oliphant Dec. 20, 19271,842,940 Jannin Ian. 26, 1932 1,900,898 Christie Mar. 14, 1933 FCREIGNPATENTS 561,787 France Aug. 17, 1923

